1. Field of the Invention
This invention relates to a so called matrix switcher apparatus (matrix routing switcher apparatus) adapted to arbitrarily distribute a plurality of channels input thereto, e.g., for video signals or audio signals, etc. to a plurality of outputs thereof.
2. Description of the Related Art
At a location where a plurality of devices (e.g., video tape recorders (VTRs)) are employed to carry out, e.g., editing work, such as, for example, in broadcasting stations or post productions, a so called matrix switcher apparatus (matrix routing switcher apparatus) may be used for arbitrarily distributing a plurality of channels from these devices (VTRs) to outputs of a plurality of channels (editing rooms, etc.). Namely, as shown in FIG. 1, in the case of transmitting signals (video signals) on respective channels from, e.g., 32 VTRs 101 to 132 within a VTR room 100, e.g., with these signals being distributed over 8 channels to four editing rooms 151 to 154, signals from respective VTRs are first transmitted to a matrix switcher apparatus 140. Then, these signals are distributed and transmitted to the respective editing rooms by the matrix switcher apparatus 140.
In such a matrix switcher apparatus, the matrix size required varies diversely depending upon the scale of the system using the matrix switcher apparatus. Namely, as the number of VTRs or the number of editing rooms is increased, the matrix size of the matrix switcher apparatus becomes larger. The matrix size of the matrix switcher apparatus at this time is ordinarily expressed as the number of inputs (the number of input channels) .times.the number of outputs (the number of output channels). For example, when the matrix size is expressed as 16.times.16, a matrix switcher apparatus having 16 input channels and 16 output channels is provided. Further, e.g., when the matrix size is expressed as 32.times.32, a matrix switcher apparatus having 32 input channels and 32 output channels is provided. Switches are arranged on the 16.times.16 or 32.times.32 cross points, respectively. When any switch is selected, a distribution of input channels is carried out.
This matrix size ranges from 16.times.16 to 256.times.256. Hitherto, in order to cope with such various matrix sizes, a system of cascade-connecting basic units (e.g., 16.times.16 or 32.times.32) has been adopted to increase the scale of the matrix. Namely, this conventional cascade system uses both basic units for increasing the number of inputs and basic units for increasing the number of outputs to carry out the cascade connection, thus to increase the number of input channels, the number of output channels, and the number of cross point matrices. With reference to FIG. 2, in accordance with this cascade system basic units 160 of e.g., 32.times.32 would be used to constitute a matrix switcher apparatus of 64.times.64. Terminals of four basic units 160 of 32.times.32 are interconnected by cascade connections 161. Thus, a matrix switcher apparatus of 64.times.64 is constituted.
However, in the case of attempting to constitute, e.g., a matrix switcher apparatus of 256.times.256 by the conventional cascade system as described above, 64 basic units of 32.times.32 must be used. For this reason, in such a large scale system, the total size and cost of the system are greatly increased.
Further, since the conventional basic units of the matrix switcher apparatus only have a few kinds of sizes, e.g., 16.times.16 or 32.times.32, etc., it is difficult to desirably change the matrix scale. For example, it is difficult to constitute a matrix having a size smaller than that of the basic unit, or a size much larger than that of the basic unit.